A182785 Primes p such that 2*p^4-1 is also prime.

2, 5, 7, 47, 79, 103, 131, 139, 149, 173, 197, 229, 307, 313, 331, 373, 439, 541, 547, 593, 659, 743, 761, 797, 853, 859, 863, 883, 919, 937, 1051, 1093, 1097, 1163, 1171, 1301, 1303, 1451, 1471, 1549, 1601, 1657, 1721, 1861, 1973, 2039, 2081, 2087, 2099, 2129, 2161, 2239, 2269, 2393, 2417, 2437, 2473, 2521

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Formula

A000040 INTERSECT A182783.

Mathematica

Select[Prime[Range[500]], PrimeQ[2 #^4 - 1]&] (* Vincenzo Librandi, Apr 17 2013 *)

Prog

(Magma) [p: p in PrimesUpTo(2600)| IsPrime(2*p^4 - 1)]; // Vincenzo Librandi, Apr 17 2013

Crossrefs

Cf. A182783, A182784, A106483 (2p^2-1 prime), A177104 (2p^3-1 prime), A309855 (2p^5-1 prime).

Sequence in context: A215213 A069356 A041653 * A358381 A041125 A293592

Adjacent sequences: A182782 A182783 A182784 * A182786 A182787 A182788

Keyword

nonn,easy

Author

Vincenzo Librandi, Dec 02 2010

Status

approved